Resistance to Ergot in Self-incompatible Germplasm Resources of Winter Rye
2009
Mirdita, Vilson | Miedaner, Thomas
The poor progress in breeding for resistance to ergot (Claviceps purpurea [Fr.] Tul.) in rye (Secale cereale L.) is attributed to the lack of appreciable genotypic variation for this trait. The present study was, therefore, undertaken to evaluate 52 indigenous and exotic genetic resources and 13 open-pollinated cultivars for ergot resistance. These 65 self-incompatible populations were evaluated in four environments with each entry plot surrounded by wheat plots on four sides. Inoculation with a pathogen mixture was done thrice during flowering and harvesting was done early by hand. Resistance traits were ergot incidence and severity. Logit-transformed data were subjected to analyses of variance. The lowest disease severity in any environment was 0.18%, and that was still higher than the official threshold of 0.1% for feed. In the pooled analysis across environments, significant genotypic differences as well as genotype x environment interaction were present. The correlation between ergot severity and pollen shedding was not significant indicating that genotypic differences were not affected by pollen shedding. Broad-sense heritability (h²) estimates were moderate (0.54-0.65). 'Halo', an old German cultivar, and the genetic resources 'Schmidt-Roggen' and 'Dukat', had low ergot severity (Halo having the lowest severity) as well as low disease incidence. The results document a significant, but moderate genotypic variance for ergot resistance among self-incompatible rye that can be exploited to breed ergot-resistant rye.
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